Tin-doped indium oxide (ITO) is an enabling material for a growing number of applications that require a highly-conductive and transparent surface, including solar cells, liquid-crystal, plasma and touchscreen displays, electromagnetic shielding, and other applications. Various deposition methods (both solution and vapor) and sputtering techniques have been commonly used to produce ITO films. Existing techniques are not scalable for large-volume fabrication or very cost intensive to scale. Lately, one-dimensional nano-structured materials such as nanowires, nanofibers, nanorods, and nanotubes have received attention for their potential applications in numerous areas due to their special properties, which are distinct from conventional bulk materials. For example, metallic nanowires and carbon-based nano-structures have been tried for transparent flexible electrodes, but the poor thermal stability of metal nanowires and the poor combinations of conductivity and transparency that are available from carbon-based nano-structures limits their application to displace ITO films.
In2O3 nanowires have been also demonstrated to work as gates in a field effect transistors and as ultra-sensitive chemical sensors for NO2 and NH3, exhibiting significantly improved chemical sensing performance compared to existing thin film-based sensors due to their enhanced surface to volume ratio. More recent research efforts have demonstrated the possibility to use ITO in its nanofiber form for sensing and transparent electrode applications. It has been shown that interwoven ITO fibers can produce a web to provide an advantageous alternative to an ITO-deposited glass surface. However, applications in this embodiment are not feasible on an industrial scale since the ability to produce such ITO nanofiber webs in large scale, at high yields/volume and at high production rates has not been demonstrated.